An algorithm for compression of wideband diverse speech and audio signals

A compression scheme for diverse speech and audio signals is proposed. In this scheme, signals are analyzed with a 2-band QMF filter bank followed by the application of a modulated lapped biorthogonal transform (MLBT) to each of the filter bank channels. Subsequent encoding of transform coefficients is performed using Laplacian optimized scalar and vector quantizers, whose rates are determined by an estimated noise threshold, i.e., masking threshold. Listening tests show that the coder achieves a quality at 32 kbits/s that is preferred over the ITU G.722 coder at 64 kbits/s, for speech, music, and more diverse signals consisting of speech in the presence of eventful background sounds. Both the delay of the coder, at 40 ms, and the level of complexity are moderate